I'm gonna report this to VM. It's quite annoying to watch Channel 4 HD on here. I get these annoying black horizontal lines flashing now and again, sometimes dropped frames. Everything else is OK though. Let's see how seriously VM takes this problem.
Thanks for taking the time to post on the community.
My apologies you are having an issue with watching Ch4.
There was a fault reported in regards to this issue, which has since been closed down as resolved.
However upon checking your connection, there is an issue with the power levels which I would like to arrange an engineer appointment to check over. I've sent you a PM (purple envelope icon, right corner) with some details for you to confirm please.